The present invention relates to the field of linear drive trains and, more particularly, to improved traveler apparatus for linear drive trains in closure operators, such as garage door operators. Specifically, the present invention is directed toward an improved traveler apparatus for a garage door operator of the type which includes a screw-driven drive train with an elongated guide rail that houses a screw which drives a traveler along a track in the guide rail.
U.S. Pat. No. 3,858,452 discloses a linear drive train for a screw drive closure operator which includes an elongated guide rail with a screw channel and a track that is formed by opposed U-shaped channels in proximity to the screw channel. A screw is contained within a liner in the screw channel, and the screw engages a nut which is carried by an inner traveler to propel the inner traveler along the interior surfaces of the U-shaped channels. An outer traveler is configured to slide along the exterior surfaces of the U-shaped channels and includes a latch to selectively couple the outer traveler to the inner traveler for cooperative movement along the guide rail.
A closure operator of the aforementioned type is typically mounted within a garage or other structure, and the outer surfaces of the guide rail are susceptible to accumulation of dirt, such as dust and other particulates. Since the outer traveler in the U.S. Pat. No. 3,858,452 traveler assembly slides along the exterior surfaces of the U-shaped channels, foreign material deposited upon the exterior surfaces of the U-shaped channels increases friction and has an abrasive effect, and the resultant heat and abrasion reduce the useful life of the outer traveler. The exterior surfaces of the U-shaped channels along which the outer traveler slides should be periodically cleaned and lubricated to reduce friction and abrasion. Moreover, in a structure which contains a storage area above the guide rail, an overhanging article in the storage area may obstruct the path of the outer traveler in such a way that movement of the outer traveler along the track causes contact with the overhanging article which may fall from the storage area and inflict personal injury or cause property damage.
Accordingly, one objective of the present invention is to provide an improved traveler apparatus.
A further objective of the invention is to provide an improved traveler apparatus for a screw drive closure operator.